I have a 102C3 I'm getting ready to install 4 Carrier Air-V units on. I also wanted to ask here, has anyone mounted these and straddled the center rail? Looks like the "downspout" would be partially blocked, but that the duct from the top unit is only on one side of the overall opening. Any thoughts/experience with this?

Todd, I iinstalled 2 Carrier roof ACs on a 102A3. It's been several months, but if I recall correctly the cold air dischage duct was centered from side to side and near the rear of the 14X14 opening. The duct is a flexible fabric and could possibly be worked around the center framing member. The bus I installed these on had already had the center framing member cut and reinforcing members added.

OK guys, perfect timing. I just got back from BusN USA yesterday and just started in on my project to add the third AC and relocate the front AC. Also, I am the guy that started the other thread on straddling the center rib.

The units I am working with are the Carrier Air-V units mentioned previously. The cold air inlet does have a short flexible connection to the distribution plate. This opening is offset so that it runs from 6.5 inches to 12.5 inches - offset to the driver's side. The return opening is 2.75 inches by 14 inches running across the opening (from side to side).

So, it is possible to offset the unit about 1.5 inches (perhaps less) to the drivers side and not have the center rib disturb the cold air supply. The center rib would cover a bit of the return air opening. If your rib was 1 inch wide (mine is less on the top side close to the opening) you would cut off less than 8% of the opening. Actually it would be less than that, as there would be some clearance between the rib and the bottom of the upper unit.

Bottom line, with proper planning, for the Carrier Air-V, you can straddle the center rib with some minor offset.

Having said all of that, I am going to make a tubing frame, cut the center rib and weld in the frame. The front cross tube will be welded to a cross member to give extra structure. I did not want to offset with the Eagle, since it has a fairly rounded roof and the Carrier units are quite tall (and a bit ugly ). Any offset would probably be not be noticeable to most folks, but it would drive this engineer crazy (wife says crazier ).

I had a MC9 about 5 years ago I put 2 carriers on and they are the coolist units I ever used, But if my bus was sitting off level at all the condesation usually more than slung back over the coils would pour in on my floor or furniture I don't know if they corrected and fixed so excess could drain down the side of coach like others units.

You should weld in the side frame members first, 14" inside to inside, then cut the center frame and weld in the front and rear to finish your opening. Doing it this way, you never leave that section of the roof unsupported.